Exploring the Impact of the Microbiome on Sleep Homeostasis in Drosophila melanogaster

Name: Joshua Gluck
Major: Biology
Advisors: Dr. Stephanie Strand, Dr. Sharon Lynn (second reader)
The study of the Brain-Gut-Microbiome axis is an exciting avenue of research. The microbiome has been shown to modulate behaviors and physiology associated with activity and movement including Parkinson’s Disease, locomotion, and sleep. There are competing studies which argue whether or not the microbiome modulates the sleep homeostasis response. Sleep homeostasis in response to sleep deprivation in Drosophila melanogasteris regulated by nur, a gene which produces the secreted peptide nemuri. In order to test the effect of the microbiome on the sleep homeostasis response, wild-type, dechorionated, streptomycin-treated, and L. brevis-treated flies were sleep deprived. Relative expression of nur was compared across treatment groups to determine if one of the key regulatory mechanisms of sleep homeostasis is affected by microbial composition. Semiquantitative gel electrophoresis PCR revealed that differences in microbial composition modulated baseline sleep levels and rebound sleep, specifically in dechorionated flies. Differences in relative expression level of nur could not be detected between experimental groups, indicating that there is a relatively small difference in expression of nur induced by sleep deprivation. Microbial composition had no observable effect on expression of nur. For more precise differentiation between experimental groups, future studies should compare exact levels of transcription. Much more work needs to be done to probe the mechanisms through which the microbiome can regulate the sleep homeostasis response.